When you tell a computer to compute the average of B+, 45, 5, and *****, it just looks at you funny and gives an error message. When you tell a computer to compute the average of 83, 45, 50, and 10, it is much, much happier. Thus, in order to make our computers happy (and calculate the METASCORES), we must convert all critics' scores to a 0-100 scale. So for the letter grade scale used by Entertainment Weekly, an A represents 100, and F corresponds to zero, with the other letters falling somewhere in between. Similarly, 4- and 5-star scales and other odd grading scales are all converted to the 0-100 scales you see displayed on each of our movie, game, TV, and music pages.
Of course, we could have performed this conversion behind the scenes, and displayed the original grades on our movie, game, TV and music pages; however, we also wanted to provide you with an easy way to compare the individual critic scores against one another. It is much easier to tell the difference between an 80, a 60, and a 20 than it is to tell the difference between a B+, a $5.25, and a *. We believe that this benefit outweighs any loss in precision caused by the conversion.
And remember, if you really want to know the original grade, just click on the quote from that critic and you'll be taken to the full review